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Flashcards in ecological niche Deck (25)
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organisms place in biotic environment (relation to food and enemies) and abiotic environment (physical surroundings)


Hutchinson's niche

n-dimensional hyper volume (n=number of environmental factors)


single niche axis

zone of intolerance, zone of stress, optimal zone


fundamental niche

the range a species could occupy without competitive pressures


realized niche

the range a species actually occupies


how does environmental complexity relate to niches

the more complex an environment, the less oportunity for competition
-more species diversity


Karr and Roth experiment

-measured height of trees (to assess complexity)
-measured number of warbler types in trees
-more complexity = more biodiversity


why can phytoplankton/algae/diatoms coexist

-partially due to complexity of environment
-mostly due to varying trophic positions and different nutritional need ratios


what happens if 2 species have same needs exactly

-cannot coexist
-one will outcompete the other


Park's flour beetles

-both types have large niches when no competition
-smaller niches when coexisting
-T. castaneum wins in hot, wet environments
-T. confusum wins in cold, dry environments
-first colonizer wins in intermediate environments


Priority effect

when the first colonizer wins at competition


Gause's competitive exclusion

-When grown allopatrically, they followed logistical curve
-when raised sympatrically, p. aurelia competitively excluded p. caudatum
-p. aurelia's k was lowered though


Barnacles in intertidal zones

-Semibalanus balanoides is restricted to lower- mid tidal positions because it is sensitive to drying out
Chthamalus stellatus is restricted to upper tidal positions because of competition with the other guy


Heske's granivorous rodent experiment

-if you remove big grainivorous rodents, there will be an increase in the number of small ones
-insectivore rodents shouldn't be impacted


niche partitioning

basically figuring out how two species can coexist by sharing resources and limiting their fundamental ranges
-usually involves different use of resources


DW analysis

-figuring out the mean usage of a resource and finding the upper and lower limit by adding and subtracting the standard deviation
-no coexistance if ranges overlap


warbler example of niche partitioning

Robert McArthur found that different warblers used different sections of the same tree


temporal partitioning example

common spiny mouse and golden spiny mouse are both nocturnal, but when grown sympatrically, the golden one becomes diurnal


Diamond fruit doves

big ones eat big fruit; small ones eat small fruit


Niche partitioning between sexes

this happens


Character displacement requirements

-the differences in sympatry must be greater than in allopatry
-the differences cannot be due to founder effect
-difference must be genetic
-must have effect on resource use
-must be competition for resource
-not due to different available resources


Hutchinson's ratio

-when organisms live in sympatry, tend to have size ratios of 1:1.1 to 1:1.4
-e.g. felis canine sizes bt sexes


Historical replacement

-when one species replaces another
-slides mention azure and blue tits, but this is honestly just dispersal with some overlap
-starlings and house sparrows evict native bluebirds and flickers from cavity nest sites


contiguous allopatry

-2 species are allopatric, but the regions in which they live are adjacent to each other
-e.g. chipmunks along sierra nevada mountains
-e.g. warblers on mt. karimuni


chipmunks in contiguous allopatry

alpine, lodgepole pine, yellow pine, least

-lodgepole is most dominant, but yellow pine is dominant to the least